1. Field of the Invention
The present invention relates to golf club heads, and more particularly, to a golf club head which includes sections having different densities and materials.
2. Description of the Related Art
Presently, golf clubs can be classified into three groups: woods, irons, and putters.
Generally, woods are used by golfers at the tee area to drive the golf ball over long distances. Woods were originally constructed of wood materials, such as persimmon. While woods constructed from wood materials are still prized by many golfers, their performance may be less than optimum because of the low density of the wood material used. Therefore, the "metal wood" club was created to enhance the performance of wood-type clubs. A metal wood reproduces the shape of a traditional wood but has a head made entirely of steel or other metallic material.
Irons are generally used for intermediate strokes usually between the teeing ground and the green where the hole is located. Typically, an iron has a club head which is manufactured from some form of metal, such as steel, which forms the entire head of the club.
The third type of golf club, the putter, is used on or around the green area for sinking the golf ball into the golf hole. The club head of the putter is generally constructed of a metallic material, as in the irons.
Woods, irons, and putters all have a strike face which contacts the golf ball when the ball is struck by the golf club head.
Various strategies have been used to improve the hitting characteristics of golf club heads. One of the strategies has been to add inserts to the face of the golf club head. In designing a golf club with face inserts, the material of the insert is selected to provide the desired hitting characteristics in the golf club. The properties of the insert material, such as the weight, friction, flexural modulus, and hardness, can greatly influence the hitting characteristics of the golf club. For example, insert materials having a high coefficient of friction tend to produce a golf club that generates higher levels of spin on the golf ball, which allows the better golfer to control and manipulate the golf shot. However, the novice player may not prefer a golf club that produces high levels of spin on the golf ball as it may decrease the distance of the golf shot and may increase the tendency of the golf ball to hook or slice.
Many variations of club heads having such face inserts have been proposed. Generally speaking, the insert covers only a portion of the face of the golf club head and extends into the club only for a portion of the depth of the club head. Often, the club head has a backing material into which the insert is placed. Examples of golf club heads having inserts can be found in U.S. Pat. Nos. 4,883,275, 5,358,249, 5,405,136, 5,423,535, 5,489,094 and 5,575,472.
Another strategy for improving the hitting characteristics of golf club heads is to adjust the weight distribution within the club head. It is well known that the weight distribution in the head affects the tendency of the club head to rotate about the golf club shaft during ball/club impact, especially when the ball/club impact occurs in a position on the club face other than the center of gravity. Various weighting techniques have been attempted to reduce this rotational tendency by changing the weight distribution in the club head. Such techniques often involve either perimeter weighting in which the weight is distributed to the perimeter areas of the club away from the center of the club head, or heel-toe weighting in which materials having different densities are used in the heel, toe and center portions of the club head in order to distribute more weight in the heel and toe of the golf club.
One form of perimeter weighting uses perimeter weight inserts. The use of lower density face inserts also may serve to distribute weight to the perimeter of the club head. Perimeter weighting characteristics can also be achieved by shaping a club head to produce a cavity in the back of the club thereby producing a complex shape wherein the weight of the club is greater along the perimeter of the club head. One version of the heel-toe weighting involves fabricating a club head wherein high density alloys are used in the heel and toe portions of the club head and a low density alloy is used in the center portion of the club head. Examples of perimeter weighting and heel-toe weighting techniques can be found in U.S. Pat. No. 4,992,236.
While the use of perimeter weighting, heel-toe weighting and face inserts in the design of golf club heads has improved the performance of golf clubs, these techniques have also raised the price of these specially designed golf clubs as the manufacturing and assembly operations used in producing these types of club modifications are relatively complex.
Therefore, there is a continuing need in the art for a golf club head that combines the performance characteristics of golf club heads having perimeter weighting and heel-toe weighting and the performance characteristics of golf club heads using face inserts, and can provide a better feel and a head structure which limits the adverse effects of an off center ball/club impact while achieving manufacturing cost efficiencies not possible with the complex manufacturing operations used in present golf club designs.